clear cell Renal Cell Carcinoma (cRCC) account for greater than 90% of Kidney-related malignancies. Our long-term goal is to elucidate cellular factors governing cRCC growth and metastasis as a prerequisite to development of therapeutic intervention protocols capable of alleviating the disease. There are two complimentary objectives of this proposal, namely (i) to elucidate the role of cell surface (CS) and secreted proteins (SP) in kidney tumor growth and metastasis, and (ii) to provide a mechanistic insight into a novel CS and SP accumulation phenotype. The specific aims of the project will test the hypothesis that CS and SP molecules facilitate progression of human cRCC, a kidney cancer type arising from Von Hippel Lindau (VHL) gene mutations. The hypothesis is related to the published study identifying a central role for VHL in dynamin-dependent endocytosis. In further investigating its implications, a novel CS and SP accumulation phenotype was uncovered in VHL -/- cells that is consistent with failure of VHL-mediated dynamin-dependent pathways. The project has four main experimental foci (i) to establish the identity of CS and SP accumulated in cRCC by proteomic analysis, (ii) to provide a mechanistic understanding of the observed CS and SP phenotype, (iii) to study role of the identified CS and SP in cRCC disease process, and (iv) use the knowledge gained for diagnostics and tumor-specific delivery of therapeutic agents. Together these experiments will elucidate cellular mechanisms influencing cRCC biology and their potential applications in diagnosis and treatment. Relevance: The current proposal addresses important aspects of the mechanisms of VHL-related kidney disease that should lead to immediate therapies and future discovery of novel mechanisms of tumorigenesis.